Soil Biology & Biochemistry最新文献

{"title":"Root exudation and fine texture interact to form anoxic microsites in rhizosphere soil","authors":"Emily M. Lacroix ,&nbsp;Junna Frei ,&nbsp;Egon van der Loo ,&nbsp;László Kocsis ,&nbsp;Marco Keiluweit","doi":"10.1016/j.soilbio.2025.109974","DOIUrl":"10.1016/j.soilbio.2025.109974","url":null,"abstract":"<div><div>Anoxic microsites – portions of soil without oxygen in a soil that is otherwise oxic – are important but poorly understood controls on critical biogeochemical processes. Plant roots and, specifically their exudates, are theorized to trigger anoxic microsite formation by stimulating soil microbial activity and subsequent oxygen consumption. However, direct observations of this phenomenon remain limited; even less is known about how root exudates interact with factors regulating oxygen supply, such as soil texture, to regulate rhizosphere oxygen dynamics. Here, we used reverse microdialysis to simulate root exudation in two distinctly textured soils (coarse and fine). We delivered ¹³C-labeled model root exudates to soil mesocosms over three diurnal cycles and observed that model root exudates increase anoxic volume during the day, particularly in fine-textured soil, and coincide with periods of enhanced soil microbial respiration and positive priming, and thus oxygen consumption. Targeted metabolomics and dPCR further showed that exudate addition increased the abundance of fermentation products and genes associated with anaerobic metabolisms in the rhizosphere. Overall, our results suggest that limited oxygen supply, combined with increased oxygen demand from positive priming and spatially concentrated microbial respiration of root exudates, contributed to greater anoxic microsite formation and quickly provoked anaerobic metabolisms in the rhizosphere of finer-textured soils. Given that root-induced anoxic microsites are rarely considered in biogeochemical cycles in otherwise well-aerated soils, our results inspire questions about the degree to which anoxic microsites mediate the plant influence on carbon cycling, nutrient availability, and contaminant fate in the rhizosphere.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"211 ","pages":"Article 109974"},"PeriodicalIF":10.3,"publicationDate":"2025-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145007189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Divergent impacts of partial manure substitution on soil nitrous oxide emissions dependent on phosphorus availability","authors":"Yuheng Cheng ,&nbsp;Jinbo Zhang ,&nbsp;Hang-Wei Hu ,&nbsp;Xiangyin Ni ,&nbsp;Jianbo Fan ,&nbsp;Song Wan ,&nbsp;Mengmeng Feng ,&nbsp;Christoph Müller ,&nbsp;Ji-Zheng He ,&nbsp;Yongxin Lin","doi":"10.1016/j.soilbio.2025.109975","DOIUrl":"10.1016/j.soilbio.2025.109975","url":null,"abstract":"<div><div>Manure substitution is increasingly advocated as a sustainable fertilization strategy to reduce synthetic nitrogen inputs in agriculture, although its implications for greenhouse gas emissions, particularly nitrous oxide (N₂O), remain uncertain. In subtropical regions, where phosphorus (P) deficiency is common, the effectiveness of manure substitution in mitigating N₂O emissions under nutrient-imbalanced conditions is poorly understood. Here, we used soils collected from a 21-year fertilization experiment and conducted controlled laboratory incubations with ¹⁵N tracing techniques to examine the effects of partial manure substitution (replacing 30 % of synthetic nitrogen with manure-nitrogen) on N₂O emissions under two fertilization regimes: nitrogen-only (N, 110 kg N ha⁻¹ yr⁻¹) and nitrogen-plus-phosphorus (NP, 110 kg N ha⁻¹ yr⁻¹ + 30 kg P ha⁻¹ yr⁻¹). Our results revealed that manure substitution increased N₂O emissions by 30 % under the N-only regime, but decreased emissions by 22 % under the NP regime. These contrasting responses were closely associated with changes in gross nitrogen transformation processes. Under N-only conditions, manure substitution stimulated autotrophic nitrification and denitrification rates, leading to increased N₂O production. Conversely, under NP conditions, manure substitution reduced N₂O emissions primarily by lowering the contribution of heterotrophic nitrification to total N₂O flux, despite unchanged heterotrophic nitrification rates. This reduction coincided with significant enrichment of <em>nosZ</em> clade II genes. Overall, these findings suggest that the effect of manure substitution on N₂O emissions is highly context dependent, with P availability acting as a key regulator of microbial nitrogen transformation pathways and thereby modulating the direction and magnitude of N₂O responses to organic fertilization in subtropical Ultisols.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"211 ","pages":"Article 109975"},"PeriodicalIF":10.3,"publicationDate":"2025-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145003461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"From synthetic to biological nitrification inhibition: Advancing stabilization of organic fertilizers","authors":"Izargi Vega-Mas ,&nbsp;Aude Mancia ,&nbsp;Lucas Maggetto ,&nbsp;Hugo Murillo ,&nbsp;Alain Debaq ,&nbsp;Bernard Heinesch ,&nbsp;Francois Boland ,&nbsp;Hans-Martin Krause ,&nbsp;Hervé Vanderschuren ,&nbsp;Cécile Thonar","doi":"10.1016/j.soilbio.2025.109971","DOIUrl":"10.1016/j.soilbio.2025.109971","url":null,"abstract":"<div><div>Fertilizer type plays a critical role in nitrogen (N) cycling, influencing nitrous oxide (N₂O) emissions, soil mineral N dynamics, and microbial communities. Understanding these interactions is essential for developing sustainable fertilization strategies that balance agricultural productivity with environmental protection. This study examined the effects of mineral and organic fertilizers (OFs) on N transformations and evaluated the efficiency of the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) in mitigating N₂O losses. Results showed that OFs exhibited variable impacts on N₂O emissions depending on their composition and C/N ratio. DMPP effectively reduced nitrification-driven N₂O emissions, particularly in treatments with high ammoniacal N content. However, its efficiency was limited with animal-based OFs, suggesting a complex interaction between fertilizer properties and inhibitor effectiveness. DMPP had not direct impact on soil microbial diversity but specifically targeted the Nitrosomonaceae family and <em>Nitrospira</em> class. Beyond synthetic inhibitors, biological nitrification inhibition (BNI) emerged as a promising alternative, which we explored using rhizospheric soils from wheat landrace Persia 44 and white mustard (cv. Pole Position and cv. Verdi). These soils significantly reduced N₂O emissions, particularly when combined with OFs. The integration of BNI with organic fertilizers, especially liquid digestate, represents a promising strategy for reducing N losses while maintaining soil fertility. This study underscores the need for tailored fertilization strategies that combine chemical and biological tools to optimize N use efficiency and support environmentally sustainable agriculture.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"211 ","pages":"Article 109971"},"PeriodicalIF":10.3,"publicationDate":"2025-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145007188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vegetation restoration shapes soil organic matter chemistry and microbial processes","authors":"Shuzhen Wang ,&nbsp;Wenxin Chen ,&nbsp;Kate V. Heal ,&nbsp;Jingjing Liang ,&nbsp;Weijuan Qiu ,&nbsp;Yuanchun Yu ,&nbsp;Chuifan Zhou","doi":"10.1016/j.soilbio.2025.109970","DOIUrl":"10.1016/j.soilbio.2025.109970","url":null,"abstract":"<div><div>Vegetation restoration is a critical process for the recovery of ecosystem functioning in red soil (Ultisol) erosion areas, yet the mechanisms underlying its effects on soil organic carbon (SOC) stability and nutrient cycling remain poorly understood. By integrating ¹³C-NMR spectroscopy, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), and microbial necromass quantification, this study elucidates the dynamic coupling mechanisms among SOC composition, dissolved organic matter (DOM) molecular signatures, and microbial necromass carbon (MNC) across vegetation types and soil depths in red soil erosion areas of southern China. Vegetation restoration significantly decreased mean soil pH from 5.02 to 4.54 in topsoil (0–10 cm) (<em>P</em> &lt; 0.05). The dissolved organic carbon concentration in topsoil increased from 75.1 mg kg⁻¹ in the degraded site (CK) to 217 mg kg⁻¹ in broadleaf forest over 80 years old (BF) (<em>P</em> &lt; 0.05) and that of easily oxidizable carbon concentrations increased from 0.48 to 2.77 g kg⁻¹ (<em>P</em> &lt; 0.05). ¹³C-NMR analysis revealed a decline in the relative abundance of alkyl C in SOC with vegetation restoration, accompanied by an increase in O-alkyl C. DOM molecular characterization indicated that vegetation restoration promoted the accumulation of oxidized compounds (lignin- and tannin-like molecules) and reduced the abundance of reduced-state compounds (lipid- and protein/amino sugar-derived molecules). Thermodynamic analysis revealed that vegetation restoration decreased energy availability of DOM molecules. Vegetation restoration significantly enhanced MNC accumulation over 10-fold in both 0–10 cm and 20–40 cm soil layers compared to severely degraded zones (<em>P</em> &lt; 0.05). Vegetation restoration significantly increased bacterial Shannon diversity and drove a bacterial community-level transition toward <em>K</em>-strategists, evidenced by a significant shift in the <em>K:r</em> ratio from 0.29 to 9.20 in 0–10 cm soil layer (<em>P</em> &lt; 0.05). Moreover, the abundance of saprotroph-symbiotroph functional guilds in fungal communities increased with vegetation restoration. Path analysis confirmed that soil DOM parameters regulate microbial necromass accumulation and multi-nutrient cycling potential by mediating DOM ΔG⁰_Cox and functional diversity. This study elucidates how vegetation restoration enhances SOC stability and ecological function recovery in red soils by reshaping DOM molecular signatures and microbial life-history strategies. These findings provide a framework for understanding and promoting carbon sequestration mechanisms in erosion-prone ecosystems, emphasizing the critical role of fungal necromass and DOM thermodynamics in long-term soil C stabilization.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"211 ","pages":"Article 109970"},"PeriodicalIF":10.3,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144996043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aggregate size mediates the stability and temperature sensitivity of soil organic carbon in response to decadal biochar and straw amendments","authors":"Yalan Chen ,&nbsp;Yakov Kuzyakov ,&nbsp;Qiwen Ma ,&nbsp;Zhangliu Du ,&nbsp;Ke Sun ,&nbsp;Keqing Xiao ,&nbsp;Xinru Liang ,&nbsp;Yang Li ,&nbsp;Yunxian Zhang ,&nbsp;Xianqiang Lai ,&nbsp;Wei Fu ,&nbsp;Bo Gao ,&nbsp;Fei Wang ,&nbsp;Shishu Zhu ,&nbsp;Qun Gao ,&nbsp;Matthias C. Rillig","doi":"10.1016/j.soilbio.2025.109969","DOIUrl":"10.1016/j.soilbio.2025.109969","url":null,"abstract":"<div><div>The temperature sensitivity (Q₁₀) of soil organic carbon (SOC) decomposition governs soil-climate feedbacks, yet how soil management mediates Q₁₀ through aggregate-scale processes remains unclear. Through a 14-year field experiment comparing biochar and maize straw amendments, we demonstrated that aggregate size critically mediated SOC stability and temperature responses. Biochar addition enhanced SOC sequestration by 49–110 % while suppressing mineralization by 4.9–14 %, primarily through preferential stabilization in small macroaggregates (SMA) and microaggregates (MA) (i.e., increased benzene polycarboxylic acids and decreased ¹⁴C age and δ¹³C). These small aggregates exhibited high SOC stability and low Q₁₀ due to enhanced mineral association, and elevated microbial carbon use efficiency (+11–39 %) for microbial necromass accrual (+35–92 %). By contrast, large macroaggregates (LMA) showed limited SOC sequestration capacity due to thermal disruption of Fe-associated SOC that led to high Q₁₀. Maize straw preferentially sequestered SOC in SMA through physical occlusion (i.e., 36 % increase in MAOM, 45 % increase in Fe-oxides) but increased bulk Q₁₀ by 89 % due to temperature-sensitive decomposition of labile straw-derived C. The correlation analysis indicated that while mineral protection reduced SOC mineralization across all aggregates, its concurrent increase in Q₁₀ highlighted a warming vulnerability tradeoff. Our findings establish that biochar outperforms straw in decoupling SOC turnover from warming through aggregate-specific stabilization pathways, providing critical insights for optimizing soil amendments to mitigate carbon-climate feedbacks in agricultural systems.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"211 ","pages":"Article 109969"},"PeriodicalIF":10.3,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144930608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tropical tree-mycorrhizal types show divergent phosphorus adaptive strategies after 12-year simulated acid rain","authors":"Yuanliu Hu ,&nbsp;Ji Chen ,&nbsp;Dafeng Hui ,&nbsp;Ying-Ping Wang ,&nbsp;Xiaolin Huang ,&nbsp;Minghui Hu ,&nbsp;Yiren Zhu ,&nbsp;Yonghui Li ,&nbsp;Jianling Li ,&nbsp;Deqiang Zhang ,&nbsp;Qi Deng","doi":"10.1016/j.soilbio.2025.109968","DOIUrl":"10.1016/j.soilbio.2025.109968","url":null,"abstract":"<div><div>Acid rain is believed to exacerbate phosphorus (P) limitation in tropical forests, but how tropical trees respond and adapt to acid-induced P limitation, particularly after long-term acid rain events, remains poorly understood. We conducted a 12-year simulated acid rain (SAR) experiment by irrigating plots with water of different pH values (i.e., 3.0, 3.5, 4.0, and 4.5 as a control) in a tropical forest in southern China. Five tree species associated with either ectomycorrhizal (ECM) or arbuscular mycorrhizal fungi (AMF) were chosen to examine the changes of P fractions in their rhizosphere soils and green leaves. In ECM tree rhizospheres, SAR treatments significantly increased labile P by 27.3 % (<em>p</em> &lt; 0.05) and decreased occluded P by 11.7 % (<em>p</em> &lt; 0.05), which were positively correlated with increased phosphodiesterase activity and related gene abundance. However, in AMF trees, SAR treatments significantly reduced rhizosphere available P and foliar P by 45.9 % and 28.7 % (<em>p</em> &lt; 0.05 for both), respectively. In response, AMF trees exhibited greater plasticity in foliar P fractions than ECM trees, shifting from structural P (phospholipids and phosphorylated proteins) to metabolic P (P-containing metabolites and nucleic acid P) fractions under SAR treatments. These findings suggest that, to cope with acid-induced P limitation, ECM trees tend to adopt an acquisitive nutrient-use strategy for greater P mobilization, while AMF trees favor a conservative strategy with more efficient foliar P utilization.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"211 ","pages":"Article 109968"},"PeriodicalIF":10.3,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144928468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tree-mycorrhizal types differ in their biomass response to nitrogen addition","authors":"Guoyin Chen ,&nbsp;Yuanliu Hu ,&nbsp;Jianping Wu ,&nbsp;Richard P. Phillips ,&nbsp;Jianyang Xia ,&nbsp;Ying-Ping Wang ,&nbsp;Dafeng Hui ,&nbsp;Jianling Li ,&nbsp;Xianyu Yao ,&nbsp;Qi Deng","doi":"10.1016/j.soilbio.2025.109967","DOIUrl":"10.1016/j.soilbio.2025.109967","url":null,"abstract":"<div><div>Increasing nitrogen (N) deposition can stimulate forest productivity and carbon (C) sequestration in woody biomass, but the magnitude and global importance of this effect remain poorly quantified. By synthesizing 123 N addition experiments globally, we show that woody biomass C gain per unit N applied (hereafter “C_perN”) was best explained by tree-mycorrhizal association (i.e., trees associated with arbuscular mycorrhizal [AM] <em>vs</em>. ectomycorrhizal [ECM] fungi) and latitude. Overall, C_perN increased with latitude, and was ∼6-fold greater in AM than ECM trees due to their distinct N-acquisition strategies. Using a global map of tree-mycorrhizal distributions, we estimated that N-induced tree C sequestration was 12% lower globally and 17% lower in temperate forests when accounting for the divergent mycorrhizal-tree C_perN, compared to estimates that ignored these effects. This reduction was largely due to the predominance of ECM trees in many temperate forests. Our results suggest that in areas receiving high N loading, trees with more acquisitive nutrient use strategies (such as AM tree sepcies) may be better positioned to sequester more C than trees with more conservative nutrient use strategies (such as ECM tree species). Therefore, shifts in the relative abundance of AM <em>versus</em> ECM trees could be a critical determinant of the future forest C sink under continued N enrichment.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"211 ","pages":"Article 109967"},"PeriodicalIF":10.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144924258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tree species diversity enhances dark microbial CO2 fixation rates in soil of a subtropical forest","authors":"Xintong Xu ,&nbsp;Pengpeng Duan ,&nbsp;Xinyi Yang ,&nbsp;Dejun Li","doi":"10.1016/j.soilbio.2025.109966","DOIUrl":"10.1016/j.soilbio.2025.109966","url":null,"abstract":"<div><div>Tree species diversity (TSD) is crucial for modulating microbial processes and enhancing soil organic carbon (SOC) accumulation in forest ecosystems. However, the role of TSD in regulating dark microbial CO₂ fixation (DMCF), a key microbial pathway contributing to SOC formation, remains largely unexplored. Here, we conducted a¹³C–CO₂ labeling experiment across three CO₂ concentrations (2 %, 5 %, and 15 %) using soils from a gradient of TSD (Shannon index 0.15–3.57) in a subtropical forest. Our results revealed that DMCF rates averaged 0.27 μg C g⁻¹ soil day⁻¹ and 174.39 μg C g⁻¹ MBC day⁻¹, offsetting 0.67 %–6.16 % of total soil CO₂ emissions in a subtropical karst forest. DMCF rates were positively correlated with TSD at both 2 % and 5 % atmospheric CO₂ concentrations. In contrast, this positive relationship disappeared under 15 % CO₂, where DMCF rates peaked at intermediate TSD, suggesting a potential stress-induced decoupling. TSD influenced DMCF through its effects on soil properties, microbial communities, and SOC stability. Microbial biomass carbon and the abundance of gram-positive bacteria were identified as key drivers of DMCF, underscoring the significance of microbial community composition in regulating DMCF rates. These findings highlight the often-overlooked contribution of DMCF to SOC storage in subtropical forests and emphasize the role of TSD in enhancing SOC sequestration. This study provides novel insights into the mechanisms governing DMCF, challenging the assumption that biodiversity consistently enhances ecosystem functions under extreme climatic drivers.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"211 ","pages":"Article 109966"},"PeriodicalIF":10.3,"publicationDate":"2025-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144919631","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Planar optodes reveal spatiotemporal heterogeneity of oxic and pH microenvironments driven by dung beetle activity in soil","authors":"Gianluca Natta ,&nbsp;Theresa Merl ,&nbsp;Alex Laini ,&nbsp;Angela Roggero ,&nbsp;Antonio Rolando ,&nbsp;Claudia Palestrini ,&nbsp;Klaus Koren ,&nbsp;Ugo Marzocchi","doi":"10.1016/j.soilbio.2025.109965","DOIUrl":"10.1016/j.soilbio.2025.109965","url":null,"abstract":"<div><div>Dung beetles (Coleoptera, Scarabaeidae) contribute to soil biogeochemical cycling via dung burial and soil mixing, yet little is known about their impact on soil biogeochemistry at the microscale. We employed planar optode imaging to simultaneously resolve oxygen and pH gradients in soil bioturbated by the tunneling species <em>Onthophagus nuchicornis</em> (Linnaeus, 1758). Using a “soil sandwich” setup, we monitored spatial and temporal changes in the soil microenvironments across a vertical plane over 96 h. Beetles generated a heterogeneous network of tunnels and dung balls, leading to steep oxygen and pH gradients and an 8-fold increase in the 2D oxic-anoxic interface zones. Buried dung balls exhibited persistent anoxia, confirmed via microsensor profiling, with more than 75 % of the volume remaining anoxic for over 45 h. Oxygen depletion was coupled to a rise in pH extending millimeters beyond the anoxic zone. Using fluorescent dye-labeled nanoparticles we were also able to track dung movement under waterlogged conditions, demonstrating continued, albeit reduced, beetle activity under anoxia. The combined effects on oxygen, pH, and the organic matter redistribution enhance microbial habitat heterogeneity and are expected to favor the coupling between aerobic and anaerobic processes, such as nitrification and denitrification. Finally, we obtained quantitative estimates of soil displacement and dung removal, providing direct metrics of the ecosystem services delivered by dung beetles, including enhanced soil porosity and organic matter burial. The novel methodological approach described here provides mechanistic insights into the microscale processes underlying dung beetle-mediated soil modification, sustaining their role as soil ecosystem engineers.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"211 ","pages":"Article 109965"},"PeriodicalIF":10.3,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144919653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Challenges in integrating dissolved organic matter chemodiversity into kinetic models of soil respiration","authors":"Arjun Chakrawal ,&nbsp;Odeta Qafoku ,&nbsp;Satish Karra ,&nbsp;John R. Bargar ,&nbsp;Emily B. Graham","doi":"10.1016/j.soilbio.2025.109954","DOIUrl":"10.1016/j.soilbio.2025.109954","url":null,"abstract":"<div><div>The chemodiversity of dissolved organic matter (DOM) in soil has been proposed to influence the microbial metabolism and fate of belowground organic carbon (C). However, integrating DOM chemistry into soil C cycle models to improve predictions of C stocks and fluxes—beyond simply considering DOM pool size—remains a challenge. While recent research suggests that incorporating DOM chemodiversity into models can improve predictions of microbial respiration, there is still a lack of mechanistic understanding describing how DOM chemodiversity affects microbial metabolism and soil respiration. We evaluated whether DOM chemodiversity was a determinant of soil respiration using paired measurements of high-resolution DOM chemistry, obtained from Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS), and potential soil respiration rates from across the United States (U.S.), all data provided by the Molecular Observation Network. Our objectives were to (1) assess statistical relationships between DOM chemodiversity and microbial respiration, and (2) evaluate the ability of kinetic models to leverage DOM chemistry to explain empirical relationships found in statistical models.</div><div>Statistical regressions revealed that DOM chemodiversity (alpha diversity) was nonlinearly related to potential soil respiration rates, both independently and through its interactions with DOM and total C concentrations. In soils with relatively high DOM but low total C concentrations, potential soil respiration rates were negatively correlated with DOM alpha diversity, whereas in soils with relatively low DOM and high total C concentrations showed the opposite trend. However, when metabolic transition theory kinetic models were modified to include chemodiversity, their performance was comparable to traditional Monod kinetics approaches, which simulate respiration rates as a function of DOM concentration. The inability to account for nonlinearities in DOM chemodiversity–respiration relationships highlight an opportunity to advance substrate uptake kinetics by establishing causal links between DOM chemodiversity, microbial metabolism trade-offs, and potential interactions under varied environmental conditions.</div></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":"211 ","pages":"Article 109954"},"PeriodicalIF":10.3,"publicationDate":"2025-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144911225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}